It is known in the art to repair defects in the meniscus of the knee. The meniscus rests on the tibial platform and extends about the perimeter of the platform. Menisci create concave surfaces which provide increased surface area for contact with the femoral condyles. This increased surface area is important for transmittal of loads across the tibio-femoral joint. Damaged menisci may be removed. However, removal may result in degenerative changes in the joint. Prior art devices for repairing torn menisci include arrows which are pushed into the meniscus, screws, and staples.
The meniscal repair device of the present invention comprises an outer wall anchor, an inner meniscal anchor, and a suture or tether which connects the anchors together. The suture may be tensioned to pull the outer and inner walls of the meniscus together, in order to close a defect.
The outer wall anchor may be longitudinally shaped and have one or more holes through which sutures may pass freely. The inner meniscal anchor preferably is shaped to resist forward and reverse movement once deployed. Also, the inner meniscal anchor may be cannulated to allow a suture to slide within. Once deployed, a suture loops through the outer wall anchor and both ends of the suture traverse back through the cannula of the inner meniscal anchor. The outer wall anchor acts as an anchor against the outer meniscal wall and as a pulley for the suture to pull through for tightening. After the anchors are satisfactorily placed, the two strands of suture may be tied or locked within the inner meniscal anchor by a variety of mechanisms. Because the suture length need not be fixed until insertion is complete, the device of this invention provides flexibility in placement within the meniscus, while enabling a surgeon to pull closed the defect in the meniscus.
In an alternative embodiment, the suture loops through the outer wall anchor and one end of the suture traverses back through the cannula of the inner meniscal anchor while the other end of the suture loops back to and is permanently attached to the inner meniscal anchor. When the device is properly positioned, the single suture strand may be locked into place.
The inner meniscal anchor may take a variety of shapes, including bullet-shaped with a wide base, bullet-shaped with fins, and flared. The inner meniscal anchor may also have a variety of locking devices, including a locking ring, wedge, snap groove, or laminated sheets. Preferably, the inner meniscal anchor will seat within the meniscus, adjacent to the inner meniscal wall. Such a placement provides proper support for the suture to close the tear in the meniscus. Also, because the inner meniscal anchor seats within the meniscal tissue, it does not interfere with tibio-femoral articulation.
The device of this invention can be used to repair a variety of soft tissue defects, for instance defects in tendon. Additionally, the device of this invention can also be used to attach soft tissue, such as tendon, to bone. Thus, while the present disclosure describes embodiments of this invention for use in the repair of a defect to a meniscus, it is understood that the device of this invention is suitable for many applications involving soft tissue.
In the method of this invention, the outer wall anchor is placed within a cannulated needle. The cannulated needle may have a slot, and the inner meniscal anchor may be located outside of the needle. The needle is then inserted through the meniscus, and a push rod deploys the outer wall anchor outside of the meniscus. With tension on the suture, the outer wall anchor flips into place, providing support against the outer rim wall of the meniscus. A second push rod may be used to push the inner meniscal anchor into a passageway in the meniscus which was created by the needle. Once the anchors are satisfactorily place, the suture is tightened, and may be secured by a variety of means. Arthroscopic techniques and needle placement are known in the art. See, e.g., U.S. Pat. No. 5,320,633, hereby incorporated by reference.
The outer wall anchor and inner meniscal anchor may be made of biocompatible material such as stainless steel, titanium, cobalt chrome, and polyethylene. Preferably, biodegradable materials may also be used, including poly lactic acid and poly lactic-glycolic acid. Other biodegradable materials are known. See, e.g., U.S. Pat. No. 4,976,715, hereby incorporated by reference. The suture may be made of resorbable or non-resorbable material.
Thus, in one embodiment of this invention a device is provided for repairing a soft tissue defect. The device comprises an outer wall anchor, an inner anchor having a locking mechanism, and a suture, wherein the suture adjustably connects the outer wall anchor to the inner anchor and the locking mechanism secures the suture to the inner anchor.
In another embodiment of this invention a device is provided for anchoring soft tissue to bone. The device comprises a bone anchor, a soft tissue anchor having a locking mechanism, and a suture, wherein the suture adjustably connect the bone anchor to the soft tissue anchor and the locking mechanism secures the suture to the soft tissue anchor.
In still another embodiment of this invention a device is provided for repairing a defect in a meniscus of a knee. The device comprises an outer wall anchor for engaging against an outside wall of the meniscus on a first side of the defect, an inner meniscal anchor engaging an inner surface of the meniscus on a second side of the defect, the inner meniscal anchor having a locking mechanism, and a suture adjustably connecting the outer wall anchor to the inner meniscal anchor. Tension on the suture pulls the outer wall anchor toward the inner meniscal anchor, thereby pulling the first and second sides of the defect together to close the defect. The locking mechanism then locks the suture in place.
In one more embodiment of this invention, a method for repairing the meniscus of a knee is provided. The method employs a meniscal repair device comprising an outer wall anchor for engaging against an outside wall of the meniscus on a first side of the defect; an inner meniscal anchor for engaging an inner surface of the meniscus on a second side of the defect, the inner meniscal anchor having a locking mechanism; and a suture adjustably connecting the outer wall anchor to the inner meniscal anchor. The method also employs a cannulated needle having a push rod. The outer wall anchor is placed within the cannulated needle, the cannulated needle is inserted into the meniscus from an inner surface of the meniscus, through the defect, to the outside wall of the meniscus, the outer wall anchor is deployed with the push rod, the inner meniscal anchor is pushed into the inner surface of the meniscus, the suture is tensioned to pull the first and second sides of the defect together, and the suture is locked in place with the locking mechanism.
Additional features of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.